I. Field of the Invention
The present invention relates to wireless communication. More particularly, the present invention relates to method and apparatus for providing configurable layers and protocols in a communications system.
II. Description of the Related Art
The use of code division multiple access (CDMA) modulation techniques is one of several techniques for facilitating communication in which a large number of system users are present. Although other multiple access communication system techniques are known in the art, such as time division multiple access (e.g., TDMA and GSM), frequency division multiple access (FDMA), and AM modulation schemes such as amplitude companded single sideband (ACSSB), the spread spectrum modulation techniques of CDMA have significant advantages over these other modulation techniques for multiple access communications systems. The use of CDMA techniques in a multiple access communications system is disclosed in U.S. Pat. No. 4,901,307, entitled xe2x80x9cSPREAD SPECTRUM MULTIPLE ACCESS COMMUNICATION SYSTEM USING SATELLITE OR TERRESTRIAL REPEATERS,xe2x80x9d issued Feb. 13,1990, and U.S. Pat. No. 5,103,459, entitled xe2x80x9cSYSTEM AND METHOD FOR GENERATING SIGNAL WAVEFORMS IN A CDMA CELLULAR TELEPHONE SYSTEM,xe2x80x9d issued Apr. 7, 1992, both assigned to the assignee of the present invention and incorporated herein by reference.
CDMA systems are typically designed to conform to one or more particular CDMA standards. Examples of such CDMA standards include the xe2x80x9cTIA/EIA/IS-95-A Mobile Station-Base Station Compatibility Standard for Dual-Mode Wideband Spread Spectrum Cellular System,xe2x80x9d the xe2x80x9cTIA/EIA/IS-35 95-B Mobile Station-Base Station Compatibility Standard for Dual-Mode Wideband Spread Spectrum Cellular System,xe2x80x9d the TIA/EIA/IS-98-A, -B, and -C standards entitled xe2x80x9cRecommended Minimum Performance Standard for Dual-Mode Spread Spectrum Cellular and PCS Mobile Stations,xe2x80x9d and xe2x80x9cThe cdma2000 ITU-R RTT Candidate Submission.xe2x80x9d New CDMA standards are continually proposed and adopted for use.
Each CDMA standard defines an air interface protocol used by that standard to support communication between communicating devices (i.e., between an access terminal and a radio network). The air interface protocol defines the mechanisms by which particular functions are to be performed, and may encompass a number of protocols that enable implementation of various functions.
Conventionally, each CDMA standard adopts a particular air interface protocol that performs a number of functions and is identified by a unique revision number. New functions can be implemented by defining new attributes, messages, and state machines, usually within the framework of the existing air interface protocol. A new air interface protocol is then defined that includes the new attributes, messages, and state machines along with other previously defined attributes, messages, and state machines. Similarly, if an existing protocol is modified or updated, a new air interface protocol is defined and a new revision is assigned.
Conventionally, each communicating device (e.g., each access terminal and radio network) is designed to support one or more complete revisions of the air interface protocol. Because the entire air interface protocol is defined by a single revision, each communicating device is required to support all required functions in a particular revision if it wishes to support any function in that revision. The communicating devices are typically designed to support one or more revisions (e.g., a range of revisions). Communication between the access terminal and radio network is then achieved using any one of the commonly supported air interface protocol revisions.
The desire for increased wireless functionality and capacity has resulted in ever more complex air interface protocols. In particular, the air interface protocols have evolved to perform numerous complex functions, including voice communication, data transmission, and so on.
The conventional method of defining a new revision for each new air interface protocol was adequate for more xe2x80x9csimplexe2x80x9d protocols in the original CDMA system design. As the number of functions and their complexity increase, the conventional method is cumbersome and inadequate. The conventional method also does not easily support the implementation of additional functions in an existing air interface protocol or implementation of a subset of the functions in the air interface protocol.
Thus, an air interface protocol structure that efficiently supports implementation of a variety of functions is highly desirable.
The present invention provides techniques used to implement configurable layers and protocols in a communications system. The layers and protocols of an air interface layering architecture are modular in design and can be modified and upgraded to support new features, perform complex tasks, and implement additional functionality. An access terminal and a radio network can communicate using the layers and protocols commonly supported by both, and this determination can be made at the time a communications session is opened. A basic set of layers and protocols supported by the access terminal and radio network ensures a minimum level of compatibility.
An embodiment of the invention provides a method for configuring a layer or protocol prior to commencement of data communication between a first entity (e.g., an access terminal) and a second entity (e.g., a data network). In accordance with the method, a set of one or more layers and one or more protocols is selected for negotiation, with each selected layer and protocol corresponding to an attribute to be negotiated between the first entity and the second entity. For each selected attribute, a list of selected attribute values is determined, with the list including one or more attribute values considered acceptable to the first entity. A list of selected attributes and their associated attribute values are sent from the first entity and, in response, a list of processed attributes and their associated lists of processed attribute values are received. Each list of processed attribute values includes one or more attribute values considered acceptable to the second entity. The layers and protocols in the first entity are then configured in accordance with the received list of processed attributes and their associated processed attribute values. In an embodiment, each processed attribute is associated with one processed attribute value. In an embodiment, the layers and protocols in the first entity are configured with their default values if corresponding processed attribute values are not received at the first entity.
The first or second entity, or both, can implement a state machine having a number of states including: (1) an inactive state indicative of inactivity prior to a session negotiation, (2) an initiated state indicative of the session negotiation over the list of selected attributes, and (3) an open state indicative of active communication between the first and second entities. The initiated state can be implemented to include (1) an access terminal initiated state indicative of the session negotiation over attributes selected by the access terminal, and (2) a radio network initiated state indicative of the session negotiation over attributes selected by the radio network.
A communications session between the first and second entities can be established by sending an open-request message from the first entity and receiving an open-response message that indicates an acceptance or rejection of the request. The open-request and open-response messages can be sent and received via common communications channels.
The selected attributes and their associated attribute values can be sent via one or more configuration-request messages, and the processed attributes and their associated attribute values can be received via one or more configuration-response messages. The messages can be identified by an entity identifier assigned to the first entity. The elements in each list of selected attribute values can be arranged in an order based on preference of the first entity, and the elements in the received configuration-response messages can be received in an order corresponding to the order of the elements in the configuration-request messages. The configuration information can be sent and received via dedicated communications channels.
The first and second entities can communicate via default layers and protocols prior to completion of the configuration of the negotiated layers and protocols. In one implementation, if the first and second entities both select a set of attributes to be negotiated, the negotiation over the set selected by the first entity is completed prior to negotiation of the set selected by the second entity.
Another embodiment of the invention provides a method for providing configurable layers or protocols, or both, in a communications system. In accordance with the method, a set of default layers and protocols is maintained for communication between a first entity and a second entity. Similarly, a set of zero or more configurable layers and one or more configurable protocols, or a combination thereof, is maintained for communication, with each configurable layer and protocol corresponding to an attribute that can be negotiated between the first and second entities. A set of configuration messages is provided that can be used for sending and receiving configuration information related to each configurable attribute. A state machine is provided to track the operating state of the first entity. The state machine can include the phases and sub-phases described above.
The set of default layers and protocols typically includes a configuration protocol used for sending and receiving messages that support negotiation and configuration of the set of configurable attributes. The configuration messages can be implemented at a session layer of the communications system. Each configuration message can include an entity identifier that identifies the first entity and a transaction identifier that identifies a particular instance of the configuration message.
Yet another embodiment of the invention provides an access terminal in a spread spectrum communications system that includes a controller, an encoder, a modulator, and a transmitter. The controller receives and processes data (e.g., traffic and signaling data), the encoder encodes the processed data, the modulator modulates the encoded data, and the transmitter converts the modulated data into an analog signal suitable for transmission over a transmission medium. The controller implements a set of layers and protocols used to support data transmission, with zero or more of the layers and one or more of the protocols, or a combination thereof, being configurable by the access terminal prior to the data transmission.
The access terminal can further include a receiver, a demodulator, and a decoder. The receiver receives a forward link signal, the demodulator demodulates the received forward link signal, the decoder decodes the demodulated signal, and the controller configures one or more of the configurable layers and protocols based, in part, on the decoded data from the decoder.
The invention further provides method and apparatus suitable for implementing configurable layers and protocols at the radio network.